Any idea what might be the OEM of this Sofirn 21700 battery?
It’s a guess but chances are it’s a Samsung 40T
The manufacturer is Shockli.
I thought shockli didn’t manufacture cells, just rewrapped them.
It may be Lishen brand. Check the liitokala 21700 cells tested by HKJ. I think there are two models of Lishen 21700 cells.
Forgot to post results.
The Sofirn 4000mAh 21700 (got it bundled with Sofirn C8F-21700) appears to have 4000mAh capacity (MC3000: 4.20v drain at 0.75A discharge current, cut-off 2.50v)
The iJoy 3750mAh 21700 only registered 3600mAh.
The IR tests are the lowest results after reseating the battery a few times… Looks like they’re similar IR.
(it seems the contacts of my MC3000 is not so good nowadays, I generally have to reseat batteries several times to get the lowest readings, unlike before when I only did to reseat maybe twice to get a good reading…)
This is the size for the new model Tesla. I was wondering when they would hit the hobby market.
You might want to wipe the rails (where the springed connections are mounted) thorougly with some dry (or slightly alcoholic) cloth periodically (once per 3-6 month probably will be enough).
I had the exact same problem with Miboxer C2-4000, and after I did as above (I did not remove the cover, just wiped, where I could access them), my readings were much better.
I also have SKYRC MC3000 - and probably I will wipe its rails, too.
do you happen to know the continuous discharge rate of this cell?
I got 4330maH for the Sofirn 21700 that came un my IF25A, tested with a btc3100… yes, a flattop 21700 fits.
What was the label, 4000 or 4800?
4000maH
hm…im guessing u dont know how much discharge rate it can handle?
Sorry, no
ok, thanks anyway
Unless you got the 4800mAh cell in a 4000mAh wrapper, your BTC-3100 is likely overestimating the capacity (not uncommon for that charger).
I bought 20 new LG 2850mah cells, and they all came between 2830 and 2849. Same for dozens of other cells and capacity. The ONLY two cells to ever come up over capacity is my sofirn 4000 mah 21700 and my wurkkos 4800mah. Thats it. I think that two high out of dozens…if not hundreds … of cells is probably unlikely. That includes liion and nimh… aa,aaa,26650, 18650, 21700, 14500.
You must have gotten lucky and gotten the 4800 mAh cell in the 4000mAh wrapper. Nice. Funny enough, Sofirn’s store page lists the IF25a as coming with a 4800 mAh cell but the pic shows the 4000 mAh one so there could indeed be a bit of cell lottery going on. I vaguely recall reading something similar with regards to their 5500 mAh 26650’s.
Edit: found this:
Yesterday, I got in a wurkkos hd20… thats the 4800mAh 21700 I mentioned above. It came in at exactly 5000maH. I suspect that they are rewrapping the same third party cells. But the 4000 came in at 4330 and the 4800mAh came in at 5000mAh. None of my sofirn 18650s or 26650s has ever come in above stated capacity. Only these 21700…
interesting…because the person i asked, she said the 5500mah are their old batteries, whereas the 5000mah are the new PLB cells.
well all my 18650 from sofirn so far have come above the rated 3000…altho not by much, always between 3000 and 3100 lol